I don't have anywhere cold in my house, so I put my ants (Lasius Niger) in the fridge to hibernate yesterday.

I've put a thermometer in there to check the temperature and it's 3.5°c in there. The thermometer is one of those digital ones that tells you the minimum temperature too, and apparently at some point it has hit 0.5°c. Which is obviously a bit too cold.

Obviously I've been stupid, and should have checked the temperature first. But now that I'm where I am, what do I do?

Do I leave them in the and hope for the best? Take them out and skip hibernation? Or are they just inevitably dead from hyperthermia already?